Ground Loop Heat-Pump Piping

NL Master Specification Guide

for Public Funded Buildings

Re-Issued 2016/01/25 Section 23 21 13.33 – Ground-Loop Heat-Pump Piping Page 1 of 6

Part 1  General

1.1  RELATED SECTIONS

.1  Section 01 33 00 - Submittal Procedures.

.2  Section 01 35 29.06 – Health and Safety Requirements.

.3  Section 01 74 21 - Construction / Demolition Waste Management and Disposal.

.4  Section 01 78 00 - Closeout Submittals.

.5  Section 23 05 05 – Installation of Pipework.

1.2  REFERENCES

.1  American Society for Testing and Materials (ASTM)

.1  ASTM D1693, Standard Test for Environmental Stress Cracking of Ethylene Plastics.

.2  ASTM D3035, Standard Specification for Polyethylene (PE) Plastic Pipe (DR-PR) Based on Controlled Outside Diameter.

.3  ASTM D3261, Standard Specification for Butt Heat Fusion Polyethylene (PE) Plastic Fittings for Polyethylene (PE) Plastic Pipe and Tubing.

.4  ASTM D3350, Standard Specification for Polyethylene Plastic Pipe and Fittings Materials.

.2  Canadian Standards Association (CSA)

.1  CSA C448, Design and Installation of Earth Energy Systems.

.3  International Ground Source Heat Pump Association (IGSHPA)

.1  Installation Manuals.

.4  National Fire Protection Association (NFPA)

.1  NFPA 704, Identification of Hazardous Materials.

1.3  SUBMITTALS

.1  Submittals: in accordance with Section 013300 - Submittal Procedures.

.2  Submit manufacturer’s catalog sheets, specifications and installation instructions for each item specified.

1.4  Quality Assurance

.1  Geothermal System Installer’s Qualifications Data:

.1  Name of each person who will be performing the geothermal work and their employer’s name, business address and telephone.

.2  Names and addresses of 3 similar projects that each person has worked on.

.3  Copy of installer’s personal experience demonstrating the use of thermal fusion techniques for polyethylene piping.

.4  The persons performing geothermal work shall be personally trained in polyethylene pipe fusion techniques by IGSHPA or piping manufacturer, personally experienced in geothermal work and shall have been regularly employed by a Company performing geothermal work for a minimum of 2 years.

.2  Geothermal System Supervisor’s Qualifications Data:

.1  Name of person overseeing the geothermal work and their name, business address and telephone number.

.2  Names and addresses of 3 similar projects that the supervisor has overseen during the past 5 years.

.3  Copy of installer’s personal experience demonstrating the use of thermal fusion techniques for polyethylene piping.

.4  The supervisor overseeing the geothermal work shall be personally trained in polyethylene pipe fusing techniques by IGSHPA or piping manufacturer, personally experienced in geothermal work, and shall have been regularly employed by a Company performing geothermal work for a minimum of 2 years.

.3  Geothermal System Contractor’s Qualifications Data:

.1  Names and addresses of 3 geothermal projects that the contractor has completed during the past 5 years.

.2  The contractor shall have completed geothermal work on at least 3 projects with ground loop heat pump piping within the last 5 years.

.4  IGSHPA Installation Manuals: Maintain one copy on site for review.

.5  CSA C448-02: Maintain one copy of site for review.

1.5  regulatory requirements

.1  Perform field testing of piping systems in complete accordance with the local utilities and other agencies having jurisdiction and as specified.

1.6  Product condition

.1  Protection: During test work, protect adjacent buildings, equipment, vehicles, etc., against damage from testing activities.

1.7  sequencing and scheduling

.1  Transmit written notification of proposed date and time of tests to the Owner’s Representative at least two (2) working days in advance of such tests.

.2  Perform cleaning and testing work in the presence of Owner’s Representative.

1.8  warranty

.1  Manufacturer’s Warranty: Minimum 50 years warranty for polyethylene piping from date of Substantial Completion.

.2  Special Warranty: 25 years for butt fusion welds in polyethylene piping against leakage from date of Substantial Completion.

1.9  WATER, SILT AND SOIL CONTAINMENT AND REMOVAL

.1  The Contractor shall submit a detailed proposal outlining his proposed methodology for containing, removing and runoffs created by the well drilling and piping installation.

.2  Dewater each borehole during drilling utilizing an interceptor and water sump tank arrangement. Remove water from site in a manner in accordance with all authorities having jurisdiction.

Part 2  PRODUCTS

2.1  HIGH DENSITY POLYETHYLENE (P.E.) PIPE AND FITTINGS

.1  Pipe and fittings shall be manufactured based on polymers made with ethylene as the sole monomer, which meet the requirements of PE Type III for water distribution.

.2  PE Type III pipe shall have a 23.2 kPa design stress at 23°C which is listed by the plastics pipe institute (PPI).

.3  The piping shall be PE3408 (high density polyethylene) with minimum cell classification 345434C per ASTM D 3350. Resistance to environmental stress cracking is critical to long life expectancy. Therefore, as a more stringent requirement, the piping shall experience zero failures (Fo) after 5,000 hours under condition “C” (100% reagent @ 100°C) when tested in accordance with ASTM D1693. A 50 year limited warranty (in writing) must be issued by the pipe manufacturer. U-type fittings shall be shop fabricated under quality controlled conditions of the same material designation and shall be ASTM D-3261 certified.

.4  Pipe shall conform to ASTM D3035 and ASTM D3261 for butt fusion fittings. U-bend joints shall be butt heat fused or socket welded.

.5  Pipe must be designed and fabricated by manufacturer specifically for geothermal heat pump applications.

.6  The complete assembly of piping within the borehole must be continuous without any joints except at the bottom U-BEND located where only a thermally fused joint or socket welded joint will be acceptable.

.7  All piping shall be sealed at the factory and contain a compressed air charge. The presence of the air charge must be witnessed at the site prior to hydrostatic testing. Piping without an air charge will not be accepted.

2.2  anti-freeze

.1  Provide a 25% by volume solution of polypropylene glycol charge and water for all the entire ground source heat pump closed loop piping.

.2  The performance characteristics shall be as follows:

.1  Viscosity shall be no more than 5.00 centipoise at –1.1°C with blend for – 9.4°C freeze protection.

.2  Specific heat shall be 1.05 at 21°C with blend for –9.4°C freeze protection.

.3  Specific gravity shall be 0.982 at 10°C with blend for –9.4°C freeze.

.4  Pressure drop and Reynolds Number for a 11.3 l/m flow in NPS ¾ SDR-11 PE pipe of a –1.1°C mixture for a –9.4°C freeze protected blend shall be no more than 0.86 m of HD per 30.0 m of pipe and no less than Re = 2028 respectively.

.3  The fluid shall mix easily and readily with water and shall not damage or corrode common tools.

.4  The fluid shall have a good or excellent material compatibility with iron, copper, red and yellow brass, polyethylene, PVC, Viton, Buna “n” neoprene and nylon and shall include an oxygen scavenger blend to reduce any corrosion capability. The fluid shall not have a low surface tension to prevent leakage.

.5  The fluid shall have a NFPA 704 Health rating of 0 (least risk).

.6  The Contractor shall provide a certified test report from a recognized lab stating glycol concentration.

.7  The product shall be available in plastic 19 liter pails, plastic 208 liter drums, or bulk tanker.

2.3  borehole grout

.1  Provide grout for each of the boreholes as indicated on the drawings.

.2  Grout to be a single componite bentonite grout consisting of 25% solids and polymer free mixed with water as follows: 68L water per 22.7 kg bentonite grout.

Part 3  EXECUTION

3.1  GEOTHERMAL BOREHOLE PIPING INSTALLATION

.1  The contractor shall obtain all necessary permits associated with the described work.

.2  The vertical holes shall be drilled no closer than 8.0 m apart and shall be held open by a “mud” casing so that the piping can be inserted. The piping shall be tested in accordance with other sections of this specification prior to insertion. Loops must be installed from or by a mechanical device so that the pipe is not rolled out on the ground before installation.

.3  Install polyethylene piping in accordance with details on drawings.

.4  The piping shall be capped and protected for future connection.

.5  Approved borehole seals should be tightened to manufacturer’s specifications.

.6  The entire piping system shall be pressure tested in accordance with other sections of this specification before any backfilling of trench is permitted.

.7  The Owner’s Representative shall be notified two (2) working days prior to the test and shall, at his discretion, witness the test.

.8  The contractor shall maintain an accurate record of all borehole locations and at the completion of the work, deliver to the owner a set of “as-builts” site plans.

3.2  GROUNTING BOREHOLE

.1  Bore holes in vertical heat exchangers shall be tremi-grouted. Grouting of vertical heat exchangers shall be done in accordance with jurisdictional requirements of IGSHPA standards. Grouting shall immediately follow the completion of drilling and installation of each borehole piping. A large capacity grout mixer/separate holding tank are required and a minimum of 25mm diameter polyethylene tubing shall be used as the tremi-grout pipe. The tremi-grout pipe shall be attached to the u-bend heat exchanger before it is lowered into the ground.

.2  Grouting procedures to be as follows:

.1  Monitor the grouting operation to ensure grout is being adequately mixed in correct proportions and that the viscosity is adequate for pumping down the borehole.

.2  The grout contractor should have spare grout pipes, hoses, fittings, readily available on site.

.3  A screw-type pump or a piston pump shall be used to pump grouts down the boreholes.

.4  A 75 to 100 mm inside diameter suction line and a 25 to 50 mm discharge line shall be used.

.5  Bentonite based grout shall be used mixed with water in proportions recommended by manufacturer. For Volclay Grout II (25% solids) utilize a mixture of 68 L per 22.7 kg of grout. Cement based grout will not be used.

3.3  PIPING SYSTEMS TEST

.1  The contractor shall provide all necessary equipment and shall perform all work required in connection with all piping system tests.

.2  At the water working pressure of the pipe installed, all water piping systems shall be tested. Each section tested shall be slowly filled with water. Care shall be taken to expel all air from pipes. If necessary, the pressure, as measured at the point of lowest elevation, shall be applied for not less than ½ hour. When the test pressure has fallen over 5%, the point of leakage shall be found, repaired and tested repeated. This procedure shall be followed until the piping systems have been proved absolutely tight. The use of any chemicals, any “Stop-Leak” compounds, any mastic or any other temporary means shall not be used for repairing leaks during or subsequent to these tests.

.3  Polyethylene pipe testing:

.1  Prior to insertion of the pipe, the contractor shall assembly the “U Bend” and piping, cap both ends, and air pressure test the piping to a pressure of 862 kPa. The test must be maintained for 8 hours minimum without the pressure falling more than 20 kPa.

.2  Loops shall pass the test at the following milestones:

.1  Before insertion into hole.

.2  After insertion into hole.

.3  Contractor is responsible to provide evidence of and certification of pressure testing, and acceptance of all work performed by signature of the Owner’s Representative.

END OF SECTION